


In the End

by rane_ne



Category: Undertale (Video Game)
Genre: And Gaster's, Angst, Dark, Gen, Genocide Route, Major spoilers for the game, Self-Introspection, Theory about Sans's past, Very Heavy Angst
Language: English
Status: Completed
Published: 2015-11-15
Updated: 2015-11-15
Packaged: 2018-05-01 16:36:14
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,793
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5213012
Author URL: https://archiveofourown.org/users/rane_ne/pseuds/rane_ne
Summary: <blockquote class="userstuff">
              <p>This world was no different from his, in the end. </p><p> <br/>Genocide route, Sans-centric.</p>
            </blockquote>





	In the End

**Author's Note:**

> This takes place before Frisk meets Sans in the genocide run. Basically my theory about Sans's past (based on canonical cues + other theories I've read about) and his connection with Gaster. Be prepared for major angst and a not so happy ending.
> 
> Note: If Wingdings registered on Ao3, I woulda definitely made all of Gaster's text like that. Sadly, it doesn't. ]:  
> 11/14/15. EDIT: Fixed Sans's dialogue format! (Removed end asterisks)

In the beginning, Sans remembered a hand beckoning him into the contraption of lights. 

He remembered the unbearable stench, fumes from the lab mixing in with the oily odor of gears, wires welded together with magic to create this... this monstrosity that he couldn't fully deem a 'success.' He remembered how deeply the glow of blue bounced off the machine's metallic walls; the eerie, sporadic splash of red that flickered on and off the console as he moved a shaking gaze over its velvet interior. He remembered the terrible sorrow in those empty eye-sockets – a skull mutilated beyond recognition, sinewy flesh slipping through the fissures lined along its face – as his colleague crooked a finger at him through the glowing doors that opened only from the inside, cracked lips moving to speak words that held no sense, at the time, to his ignorant mind: 

_"You must stay determined when you reach that other world. Promise me you'll stop the human, no matter what."_

None of the others had been there that night; it was a quarter till three, and he knew everyone else was sleeping, locked underground with only the few memories of sunlight, dazzling surface soil beneath their cold, buried soles, to keep them warm during the winter. When he'd received the call from the ever elusive doctor (not "M.D." but "W.D." for some reason), he'd grabbed only a jacket and his identification badge, still wearing shorts and slippers and yawning with drowsiness. Initially spurred on by a curiosity to see this solution that would "save them all," Sans couldn't fathom the odd fear he felt at the sight of the other skeleton's grim visage—a face he realized couldn't have possibly come from their world, a voice that hadn't sounded as distant in his memory. Nor could he explain, years from now, centuries and eons of time-lines later, why he then took a step in; even with confusion and hesitation, terror and reluctance crawling to squeeze gasps from his gritted teeth, he'd bounded forward to embrace the gentle lure of violet light.

He remembered the sensation of Gaster's bony hand on his shoulder before the world blacked out; and he woke up to a snow-covered land that wasn't his own.

It was the same town, the same flicker of familiarity in the new faces he met—the silly skeleton who reminded him, quite endearingly, of the older brother he'd left behind; the skeleton's equally explosive fish friend, who conjured memories of his over-zealous but compassionate co-worker; the soft-hearted king who couldn't lay a finger on another soul to save his life, much like his pushover of a boss in the CORE; and _her_ , that majestic queen with gentle eyes and a surprisingly down-to-earth sense of humor, someone who sparked within him so dearly the deepest sense of loss, the loss of a best friend and of a world that he would never see again. 

Because it _wasn't_ the same. Snowdin was lovely, with friendly inhabitants and people he eventually grew to care for, but it couldn't be called 'home.'

So Sans decided to call it *home too instead.

This world was no different from his, in the end. Gray still bled from snow that first trickled down white to blanket their lives, only to collect under stained, brown souls, indentations of a past that wouldn't leave... Only agony and hopelessness remained, and all knew it. They knew they'd never see the surface; never know the warmth of a sun beaming down on their pale skin, see the soft meadows filled with bright, golden flowers. Never hear the birds singing above vast and far tree-tops, wind caressing their faces with its rich laughter. They slept, like those from his old world, with merely memories and the lingering phantom of determination, fueling them through another day; another and another and another until one day _that_ person would come to save them all. 

Before he found out the truth, he didn't want to believe _he_ was that person. 

Gaster had made a tainted machine. The awe Sans might've felt at the prospect of dimensional hopping was nothing compared to the pain he'd experienced as his bones were crushed, stretched, and reformatted inside the contraption. If he'd been a human, if he'd had guts to spill, all of his organs would've splattered onto the console, streaking the glass window with vibrant, crimson ribbons. But he recalled only horror, absolute fear clawing its way out his throat, the moment light streamed in from all around him, ray after ray of deadly photons zigzagging into the crevices of his skeletal frame. He'd only managed to shut his right eye in time as the brightest flash of blue assaulted his vision—and searing, liquid lava completely engulfed his left eye. He was lost then, screaming his voice hoarse as icy, pulsing pangs shook his entire body and tears streaked down his face in agonizing rivets. When it was over, he'd collapsed onto the floor numbly, registering a peculiar sharp edge to the images he received through his left eye. Everywhere he looked, he saw black, a void of emptiness except for the occasional floating boxes: **[Sans]** , one said, **[LV 1 / HP 1 / G 0]** ; **[ITEM / STAT / (EMPTY)]** , another one drew a list right below the first. None of it made any sense to him. Like Gaster's creation, he now felt tainted, burning feverish with a horrible knowledge – a _power_ – beyond his control. 

He discovered that this new-found sight in his left eye wasn't permanent; it wasn't even long-lasting. It took a great deal of will-power - or 'determination,' as Sans made it a habit to call - to conjure up the unique sapphire glow—which triggered the blank, black world he soon learned was "the real world." It gave him a glimpse of a chilling reality filled with boxes and commands and "stat info" on him, the people surrounding him, and all the possible worlds on their plane. It revealed to him the deadly secrets of a route that would end in disaster for every monster in the underground. It gave him a peek into Hell.

Sans had never been a truly motivated person. Not once in his life did he think he would take the initiative to change anything. He'd always held the view that if change _did_ happen, he'd be in the background silently observing the passing tides, the push-and-pull of the future reaching out to upset his daily routine. Even while working at the CORE in his original world, he'd never thought that his decisions would have any impact on their research; if _he_ would have any impact on the future of their entire race. So on that wintry day, when he stumbled out the contraption into Snowdin, he buried himself under his jacket, shut off the foreboding nervousness in his heart, and made sure his existence in *home too was just as passive. He made sure to joke away the pain and fear deep inside him. 

And in the beginning, it worked. 

Life became a pleasant monotony: building snow-castles and reading bedtime stories to Papyrus, whom he'd adopted as a brother ("older," since the skeleton had been adamant that _he_ would protect Sans and not vice versa); discussing the future of the Royal Guard with Undyne whenever they weren't fake sparring (or occasionally anime discussing with her soon-to-be girlfriend Alphys); having tea parties with Asgore on off-days or just when he wanted to have a serious conversation with a man of experience; and of course spending time with Toriel when he needed to feel... safe, _at home_ , with a warm pie and light chatter to brighten his mood, to cure the emptiness that had never and would never leave his soul. Life was boring, and he enjoyed it.

Until the first human fell through the barrier, he had enjoyed his ignorance. Eyes closed, he'd stood by even as he watched the hopes and dreams of their people fall into ruin with Chara's and, soon after, Asriel's death. Even when Toriel disappeared somewhere in the ruins, even as Asgore retreated into his castle and Alphys into her lab, even as Undyne grew colder and more reserved, rarely speaking to him unless she needed him for something, and even as Papyrus started smiling less and less as the days dragged on and the snow continued to bury them deeper underground, he did nothing. He started to have dreams plagued with blinding light and the memory of blood dripping from his mouth. He woke up with his left eye straining from its socket, deadly cobalt and screaming silently for a world that didn't exist anymore—only to see darkness and boxes and taunting words of _*i'm having a bad time, i'm having a bad time. / please ... someone help me._ And still, he did nothing. 

The years passed. More humans fell through, and Asgore fell them all. Six souls had been collected, and the harbinger was steadily sounding closer. Sans watched with hands in his pockets, listless eyes gazing up at a cloudy sky that never changed, and wondered what to do with his life. He knew what was going to happen, but there was still so much more he didn't know. What could he do, if he could do anything at all? He felt no determination to try. 

It wasn't until a week before _they_ arrived that he received a text message from an old "friend," one that would change nothing but would ultimately set in motion the events of his already pre-determined fate. The number was unknown, a person named "G" who spoke in a language that only he, oddly enough, could understand. "Remember your promise. Meet me in the blue room that only your eye can see." Sans wanted to ignore the curt demand; that bastard Gaster who had done this to him, who'd forced him from his world and stained his existence with nothing but terror... why should he agree to anything the old fool wanted? And yet he found himself automatically moving to obey, donning on his trademark jacket and slippers and tiptoeing past Papyrus's room to his secret workshop. 

The machine lay beneath cloth, just as he'd left it years ago. Just as it was when the hand had beckoned him into the contraption so, so long ago, Sans couldn't explain why he immediately flashed on his sapphire eye and entered the unknown space without hesitation. Inside, the room was small and compact, floating above him with a text box that read, **[You found the secret area.]** He followed the same hand with its crooked, beckoning finger through the door and across the bridge between his world and _that_ world; a monstrosity which shouldn't have been created in the first place. Gaster stood impatiently before him, gruesome face the same as he'd remembered it—cracked, bleeding, and smiling without feeling. In another time, Sans thought that he might've looked just like Gaster, if he ever let himself go that badly. 

"There's no time to waste," the skeleton said quickly, and the clinical way he spoke made Sans's heart beat faster. "I summoned you here because—"

*everyone and everything depends on me?  
Sans interrupted with a guess.  
*i'm your only hope left? you got tired of waiting on lazy old sans to make a move so you thought you'd do it for me?

Fueled with sudden anger, he stepped forward to get a better look at the skeleton, smelling the familiar, sickening stench of chemical fumes and oil that came not from Gaster but from behind him, _through_ him. The creature appeared frightened, uneasy, and unsure of what to do with his stouter counterpart.

 _good. it's about time he knows i'm not his puppet... that what he's done has finally come back to bite him in the ass._

But before Sans could say just that, a box popped up beneath Gaster's form. Red words scrawled like yarn across it: **[You realize he has died long ago, in this world.]** A pause, and the text disappeared only to be replaced by a final sentence: **[What a terrible sorrow in his empty eye-sockets.]**

Horrified, he jerked back, his jaw agape with realization. Pale, sheet-like skin, eyes which trembled with the pain of unforgotten memories, of _death_ , this creature was nothing more than a _ghost_. 

His next words were quiet, murmured. *is that why you chose me?

"Yes. I have no way of impacting this world with my form as it is now."

*you made that machine just to come to my world and take me back to yours?

"I needed a vessel to pour my powers into, one with a physical form to help me in places I couldn't reach." 

Sans took in a shuddering breath and closed his eyes. That explained the blue glow and his altered perception of reality, the mysterious tingling sensation that boiled beneath his bones... the aching desire to use his destructive power. The contraption had been more than just a means for dimensional hopping; it was a repository for magic transfer. 

*...so... this is all because you need me to stop 'the human'.

"No." Gaster's blank gaze was cold, devoid of compassion. "I need you to _kill_ them." 

Sans felt a shiver run down his spine. Sweat began to collect on his skull, bony fingers grasping tight to the hem of his jacket.  
*bro, i-i don't kill. i've never killed before. i don't even think i know _how_ to kill.  
He chuckled ruefully.  
*my stats are all 1... you realize that, right? i can't even land a single hit on undyne without hurting _myself._ what makes you think... 

"It doesn't matter," Gaster interrupted him. Thin digits reached out to clasp his shoulder, and rather than recoiling from the cool touch, Sans leaned in closer, allowing the skeleton the brief contact. "I gave you the power to make this possible. Now I've given you the knowledge to piece together the puzzles of this world, to save it." He knew Gaster was referring to the mysterious boxes and buttons all around them, the ones labeled 'Save' and 'Reset' and 'Erase.' "All I need is for you to promise me that you'll try and help us." The warm glow in the creature's emotionless eyes, so close to affection that it pained Sans with its obvious deception, made him look away. "Please."

*i... don't want to make any promises.  
He clenched his eyes shut once more.  
*i don't want... _to start over again._

 _but i'm too afraid to stop them._

He remembered the terrible pain in the woman's - _Toriel's_ \- voice as she'd pleaded for him to protect the next one that came through... the next human that would come through and destroy all he'd grown to care for. If he let them do so. If he refused to change - just like this never changing, unending world with its threat of resetting and erasing everything - then change would come to him instead; and ill-prepared as he was now, it would slaughter him completely. 

To fight and murder, as Gaster wanted him to do, or to flee and have mercy, as Toriel had wished... why did neither path seem appealing? Why did neither feel _right_? Was it because he could only see darkness around him the farther he looked and the more he thought of his future? Was it because the world bled so cold, cruel, wretched thing drowning him under ice; like his heart, like his gray, decaying soul? Was it because he knew, deep down inside, that he'd be breaking both promises in the end, no matter what he did? 

_this is why i don't make promises. this is why you guys can't trust me. this is why... i never change._

When Sans finally opened his eyes, the room was gone, and in its place was a lone text box, shrouded by black light. **[No one is here.]** A feeling close to hopelessness welled inside of him. He gasped, clutching his chest as if assaulted by a sharp pain. What time was it? How much time had passed since he'd been in this place? He needed to get out, before frost seeped into his bones and the world shifted again. Before the human arrived with their red-tinted eyes and a smile void enough to rival his never-changing one. 

He reached blindly in the dark, fingers accidentally grazing over yellow font—"))) ACT". A string of red trickled down his left eye, vision blurring around the edges as the words changed. **[You called for help.]** He couldn't control the laughter that spilled from him in the guise of long, heaving sobs, stumbling across the bridge and back into a frozen world that wasn't and couldn't truly be called 'home.'

_in the end, no one came._


End file.
